In Flogsta, a neighborhood in Uppsala, Sweden, everyone opens their windows or goes out in the streets every night at 22:00 and starts screaming! Really. It's a tradition in place since the 1970s. The area is dense with college students, and they say it is to blow off steam. Redditor TombSv linked to a video of the screams, if you want to hear it. Residents say they are so used to it that they don't pay attention anymore. Link -via reddit